In the related art, ultraviolet curable ink, which is cured by being irradiated with ultraviolet rays, is used as ink to be printed on a container such as a beer can, a juice can, a PET bottle, a shampoo bottle, or a cosmetic bottle. Further, a light emitting apparatus, which emits the ultraviolet rays, is generally used to cure the ultraviolet curable ink.
For example, Patent Document 1 discloses an image forming apparatus for forming an image on an outer circumferential surface of a can body (irradiation object) by using an inkjet head. The apparatus has a support cylinder (mandrel) which is inserted into the can body and supports the can body, the inkjet head which discharges ultraviolet curable ink onto the outer circumferential surface of the can body supported by the support cylinder, a UVLED lamp (light emitting apparatus), and the like. Further, the ultraviolet curable ink is discharged while the can body is rotated such that an image is formed on the outer circumferential surface of the can body, and the outer circumferential surface of the can body is irradiated with ultraviolet rays from the UVLED lamp such that the ultraviolet curable ink attached onto the outer circumferential surface of the can body is cured.
Patent Document 2 discloses a printing device including a transport unit which transports a print medium, six heads which are arranged in a transport direction and discharge cyan ink, magenta ink, yellow ink, black ink, orange ink, and green ink, respectively, six irradiation units (light emitting apparatuses) for temporary curing which are disposed at a downstream side in the transport direction between the respective heads and temporarily cure (pinning) dotted ink discharged onto the print medium from the respective heads, and an irradiation unit for main curing which mainly cures the dot ink and fixes the dot ink onto the print medium. Further, LEDs are used, as a light source, for the irradiation unit for temporary curing to meet requirements of reduction in weight and size of the printing device itself, and the multiple LEDs are disposed in parallel in a width direction of the print medium.